Geo-Spatial Assessment Of Cholera And Identification Of Pathogenic Bacteria Found In Selected Water Sources In Ile-Ife, Osun State, Nigeria
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Date
2016
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Abstract
This study mapped out the environmental risk factors associated with cholera in Ile-Ife and investigated the spatial relationship between cholera incidences and environmental risk factors for it. It also determined the presence of Vibrio cholerae and other pathogenic bacteria in selected water bodies in the study area. This was with a view to providing information on the predisposing and enhancing factors associated with cholera in the study area.
Recent high resolution image of the study area and a land-use/land-cover map were used to identify environmental factors associated with cholera in the study area. A Global Positioning System (GPS) unit was used to identify other point and non-point sources of environmental risks including the location of refuse dumps, abattoirs, markets, rivers and wells. Streams and river network at the LGAs were digitized. The GPS datasets were plotted on a high resolution satellite imagery of the study area and the land-use map of the study area for cross examination and visualization. The environmental factors were ranked accordingly, weights were assigned to them and a suitability analysis was carried out using ARCGIS software. Spatial analysis was carried out to stratify the study area into eight cholera risk zones. Water samples were taken from rivers and wells in each of the zones and then tested for the presence of Vibrio choleraeand other pathogenic bacteria. The result of the Vibrio cholerae and other pathogenic bacteria count per sample were used to build up the attribute for each of the water sample points on geographic information system map. The level of contamination was then displayed on the map and integrated with the cholera database to produce an environmental risk map for the study area.
Waste dump sites, abattoirs and markets were mapped out as the environmental risk factors (ERFs) associated with cholera in the study area. It was observed that there was an association between the ERFs (p < 0.001). Similarly, 18 out of the 44 waste dump sites located in the study were near the historical cholera cases. Also, seven out of the 18 markets in the study were observed to be near the historical cholera incidences. Finally, two abattoirs were selected out of 36 abattoirs to be proximal to the historical cholera cases. Furthermore, Vibrio cholerae(7.3%), Klebsiellapneumoniae(12.7%, 3.6%), Enterobacteraerogenes(9.1%, 3.6%),Citrobacterkoseri(0%, 7.3%), Escherichia coli (3.6%, 7.3%),Klebsiellaaerogenes(7.3%, 5.5%),Citrobacterfreundii(7.3%, 1.8%), Salmonella typhi(7.3%, 3.6%), Pseudomonas aeruginosa(5.5%, 1.8%),Shigelladysenteriae(5.5%, 3.6%)and Proteus mirabilis (3.6%, 0%) were identified from wells and streams in water samples respectively. The environmental risk map produced for the study showed the ranges for the colony forming unit (CFU) counts with the population at risk.
The study concluded that waste dump sites and market had the highest predisposing attribute to cholera.
Description
146p
Keywords
cholera, Vibrio, environmental, predisposing